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- [/
- Boost.Optional
- Copyright (c) 2003-2007 Fernando Luis Cacciola Carballal
- Copyright (c) 2015 Andrzej Krzemienski
- Distributed under the Boost Software License, Version 1.0.
- (See accompanying file LICENSE_1_0.txt or copy at
- http://www.boost.org/LICENSE_1_0.txt)
- ]
- [section Header <boost/none.hpp>]
- [section Synopsis]
- ```
- namespace boost {
- class none_t {/* see below */};
- const none_t none (/* see below */);
-
- } // namespace boost
- ```
- Class `none_t` is meant to serve as a tag for selecting appropriate overloads of from `optional`'s interface. It is an empty, trivially copyable class with disabled default constructor.
- Constant `none` is used to indicate an optional object that does not contain a value in initialization, assignment and relational operations of `optional`.
- [endsect]
- [endsect]
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